Former Garda commissioner Nóirín O’Sullivan did not give instructions to her legal team in relation to the dealings of whistleblower Sgt Maurice McCabe with senior officers also represented by her legal team, because she did not have direct factual knowledge of the issues, the Charleton Tribunal has heard.

The tribunal is examining whether unjustified grounds were inappropriately relied upon by the former garda commissioner to discredit Sgt McCabe at the O’Higgins Commission of Investigation.

The commission, which sat in private in 2015, investigated complaints made by Sgt McCabe about certain policing matters and about serious allegations against senior officers, including then Garda Commissioner, Martin Callinan.

Mr Michael McNamee BL and two other barristers represented the garda commissioner and several senior garda officers before the Commission.

Mr McNamee told the tribunal he never read the Byrne-McGinn report, an internal garda report into Sgt McCabe’s complaints about the Cavan-Monaghan division.

He received a copy of the report around June 2015, and brought it home along with other boxes of documents. "To be frank I never opened it, I never read it," Mr McNamee said.

Michael McNamee. Pic: Rollingnews.ie

Mr McNamee said individual officers had been able to identify themselves from code names used in a later report by barrister Sean Guerin SC, and knew that they could face allegations at the O’Higgins Commission.

He said Ms O’Sullivan did not give instructions in relation to these officers because she did not have direct factual knowledge of the issues, as she was not directly involved.

Mr McNamee said that he received instructions from the commissioner to explore background issues. The legal team also received specific instructions from three particular clients.

After arguments at the commission between Sgt McCabe and the legal teams for the commissioner on 15 May 2015, Mr McNamee drafted a document outlining the case being put by the team over the following weekend.

The letter, handed in to the Commission on Monday 18 May 2015, stated in error that at a 2008 meeting with Supt Noel Cunningham, Sgt McCabe said he made allegations against a senior officer, then Supt Michael Clancy, to force him to release directions from the DPP which had exonerated him following an investigation into a child abuse allegation.

The tribunal also heard that a report which Supt Cunningham had written in 2008, which gave an accurate account of the meeting with Sgt McCabe, was also handed in to the Commission at the same time.

Mr McNamee said he was disappointed when the error came to light a month later. Tribunal chairman Mr Justice Peter Charleton said that Justice O’Higgins had received two contradictory documents.

Michael McDowell SC, on behalf of Sgt McCabe, asked whether the document that Mr McNamee had submitted accurately reflected the instructions that the legal team had received.

The tribunal chairman said that this was subject to legal privileges which had not been waived, and the question should not be asked.

Garret Byrne BL said he sent an email to the garda commissioner’s liaison, Chief Supt Fergus Healy, on Friday 15 May which stated the legal team team felt that "it will become necessary to put to Sgt McCabe certain background issues which touch upon and concern the history of his dealings with members of Garda management”.

Mr Byrne said the email was drafted by hand by both himself and Mr McNamee, and then he typed it up on his computer.